Liquid coating composition



Eatentecl Sept. 18, 1951- LIQUID COATING OOMPO SITION John R. Fisher,Jr., Dayton, Ohio, assignor to Industrial Metal Protectives, Inc.,Dayton, Ohio, a corporation of Delaware No Drawing. Application November9, 1949, Serial No. 126,451

9 Claims. 1

This invention relates to corrosion-resisting coatings. Moreparticularly, it relates to an improved protective coating compositionand the process for manufacturing same.

Protective coatings for surfaces to be effective must be continuous. Thedried coating must be insoluble in liquid mediums which they contact andbe impervious to corrosive elements. In addition, the coatings must havehigh tenacity for the base to withstand abrasion and shock incident tothe normal use.

New types of coating material have come into use such as those disclosedin the application of Alexander McDonald, filed November 14, 1946,Serial No. 709,770, entitled Improvement in or Relating to CoatingCompositions, now Patent No. 2,509,875, and in the application of JohnR. Fisher, Jr., filed December 6, 1947, Serial No. 790,233, entitledCoating Composition and Method of Making.

The coating compositions consist basically of powdered metals suspendedin aqueous solutions of sodium silicate or in resin solutions. Thesepowdered metal base coatings have been subject to the disadvantages thatthe mixes could not be prepared a reasonable time in advance of use.

In the coatings such as were disclosed by Fisher the oils necessary fortenacious, shock-proof character, becam oxidized, losing theireffectiveness. Further, the presence of finely divided metals apparentlyaccelerated the oxidation reaction.

It is an object of the present invention to overcome the limitations anddisadvantages of the above described methods.

It is an object of this invention to provide a coating which can beprepared in advance of use.

It is another object of the present invention to a provide a coatingthat is durable.

- It is still a further object of this invention to prepare coatingswhich rapidly dry to'tough, adhering films.

It is a further-object of this invention to prepare coatings which airdry to as durable coatings as had heretofor been produced by bakingmethods. a

It is another object of this invention to prepare coatings which remainfluid and spreadable for extended periods of time, thus making forsmooth continuous films.

It is another object of this invention to produce anti-corrosion coatingusing finely divided metal powders which if used as a base coat, permitssuperimposing of additional coatings without additional treatment.

It is still a further object of this invention to provide a simplemethod of preparing coating compositions containing finely dividedmetals which do not rapidly oxidize and gel.

These and other objects and advantages will become apparent uponreferenc to the following description:

The improved coating composition is prepared by mixing at roomtemperature a solution of a low acid resin, a vegetable drying oil, asolvent, metallic drier, an aromatic distillation residue, and finelydivided metallic powder.

This composition or suspension can be applied by spraying, by brushing,or by dipping. The coating applied may be hardened by either air dryingor force drying methods. If the composition is utilized as an undercoat,it may be overlaid with enamels, wrinkle finishes or any of theindustrial finishes. As an undercoat, the composition needs only a shortperiod for surface drying, following which an overcoat can be directlyapplied, and both coatings simultaneously baked to dryness.

Heretofore anti-corrosion coatings or primers have customarily beendried and in addition many. of such coatings must have additionaltreatments to render them satisfactory for the application of finishedcoats to avoid ultimate destruction of the finished coats by the primercoat or the formation of bubbles, lumps, etc. under the finished coat.

The coating of the present invention, when used as a primer coat, hasdeveloped the unexpected property of permitting the finish coat beingapplied after a few minutes of air drying of the primer, without anyfurther treatment of the primer.

It is also possible to bake both the primer coat and the finished coatsimultaneously, thereby eliminating one baking and a large amount ofexpensive handling of mass production items on conveyor lines.

After four hours of air drying, the coating of this invention is hardenough to allow packing and shipping of the articles. In twelve hoursthe coating has acquired its final hardness which is essentially higherthan coatings produced heretoiore. If the production is to beaccelerated, it is advisable to use forced drying. The final coatingobtained thereby, however, is not at all superior to those finished byair drying.

Baking or forced drying may be carried out at temperatures in the rangeof approximately 200 F. to 400 F., the preferred temperature being atabout 225 F. In the latter case a drying time of about 30 minutes to onehour suffices. If drying is carried out with infra-red light, heatingfor only 15 minutes may be found necessary.

The low-acid resins operative for the process and products of thisinvention are those having an acid number of, or below 6, and preferablybelow 5. For instance, melamine formaldehyde resins, phenol formaldehyderesins, alkyd resins, particularly of the phthalic acideglycerol type,glyptal resins, ester gums, and lam nar gums are among those which havebeen found satisfactory. These resins are preferably used in the,

tion, have been found satisfactory. A portion of these driers may alsobe replaced by the corresponqing nese S lt A number of aromaticdistillation residues have proven satisfactory as inhibitors of theoxidation of the composition. Creosote oil in particular is preferred.Such equivalent material as naphthols, di-pentene, andthe like, may beused for this purpose The quantity of the inhibitor will vary inaccordance with the time delay desired between mixing and use.

In general, quantities ranging from approxim e y .005 er cent. e a matly per cent may be used. A quantity corresponding to 0.1 percent byweight of the composition has been found to increase storage life by 6to 12 months. k

The finely divided powder used in this coating composition may he.eemmlh t d met s u s Zine, lead, luminum, ma nesium, cad er alloysthereof. For the intended use powders Su as Zinc ha Q 5 49b h 90 centaverages less than 6 microns in size. In other words, material is ofsuch fineness that 90 per cent l as t reheh I. S- s and d 0 mesh sievePr ie ehlv he new r hould. a a 3 microns Q 5 121. 9 w e of his. tyne.wil eensiitute. pp xima ely 100 to 350 per cent by weight of thesolution nt which t e. owders ar mi ed.

T following pron tt ehs. f he, n redients have n f un to. ive sei fe tetx r s ts:

60 to 70 s. l wcid re in se utioneeeta n ing 40 to 60 per cent resin 0to 10 fl. ozs. drying oil 16 to 24 ll. ozs. solvent A; fl. oz. cobaltdrier fl. oz. lead drier 16 to lbs. zinc dust .05 to .2 fl. ozs.creosote oil In the l win e e am le ar ive for formulae s able fe t c ain o m n em tion:

Eeemn e I 85 lbs. phthalic acid-glyceroi resin, solution con,-

taining 40 to 60 per cent resin 10 /4 lbs. raw linseedoil 32 lbs.mineral spirits 1 lb. lead linoleate 1b. cobalt linoleate 2 ozs.creosote oil ne emm n te 250 lbs. zinc dust (90% of which is less than 6microns in size and preferably averaging. 3. micronsinsize) Thiscomposition is prepared by mixing the liquid ingredients together atroom temperature. To this mixture, the zinc dust is added slowly withconstant agitation until a smooth suspension is obtained.

There will be a slight foaming during the initial mixing due to thereaction of the zinc and acids present in the resins and the oils. Thisaction ceases in a few minutes and is in no Way detrimental to the finalcomposition.

Additional ex m s are as follows:

Example II 64 fl. ozs. phenol formaldehyde resin solution containing toper cent resin 8 fl. ozs. oiticica oil 16 fl. ozs. VM&P naphtha /2 fl.oz. cobalt linoleate 11. oz. lead naphthenate fl. oz. creosote oil 20lbs. zinc dust of which is less than 6 microns in size and preferablyaveraging 3 microns in size) Example III 64 ii. ozs. phenol formaldehyderesin solution containing 40 to 60 per cent resins 6 fl. ozs. perillaoil 18 fl. ozs. Stoddard solvent (Gulf Oil Co.)

fl. oz. cobalt naphthenate /2 fl. oz. lead linoleate fl. oz. creosoteoil 19 lbs. zinc dust (90% of which is less than 6 microns in size andpreferably averaging 3 microns in size) Example IV 66 fl. ozs. alkydresin 2 fl. ozs. dehydrated castor oil 20 fl. ozs. petroleum solvent(flash point 104; F. or

higher),

fl. oz. cobalt naphthanate 1i. oz. lead linoleate 2 fl. ozs. creosoteoil 18 lbs. aluminum dust (90% of which is less than 6 microns in sizeand preferably averaging 3 microns in size) Example V 67 11. ozs.Glyptal resin solution containing 40 to 60 per cent resin 1 fl. oz,linseed oil (blown) 10 ii. ozs. mineral spirits 1i. oz. cobaltnaphthanate fl. oz. lead naphthanate fl. oz. creosote oil 20 lbs. zincdust (90% of which is less than 6 microns in size and preferablyaveraging 3 microns in size) All of the above mixtures. were applied onarticles to be coated and then allowed to air-dry or toair dry for aboutIOminutes and then baked as described. The coatings obtained therefromwere extremely durable. The coatingson the articles. werenot affected byrain, salt water, or the like, which proves the excellent protectivequality of the coating and the continuity of thefilm.

The coating composition of Example I was applied to a surface whenfreshly prepared. A portion of the composition was set aside in a closedcontainer for three months. A companion coating was placed beside thecoating made when the composition was freshly prepared. Thecharacteristics. of the two. coatings were so nearly alike as to raisethe question that any differences found were in all probability withinthe range of experimental error of the testing equipment.

It will be understood that while there have been given herein certainspecific examples of the practice of this invention, it is not intendedthereby to have this invention limited to or circumscribed by thespecific details of materials, proportions, or conditions hereinspecified, in view of the fact that this invention may be modiledaccording to individual preference or conditions without necessarilydeparting from the spirit of this disclosure and the scope of theappended claims. For example, oxidizable polymer resins may besubstituted in whole or in part for the vegetable drying oil. Suchcompositions are equally well stabilized by the aromatic distillationresidues.

I claim:

1. A liquid coating composition comprising a dispersion of 16 to 20 lbs.zinc dust, the particle size of which is not larger than 6 microns andhaving an average particle size of 3 microns at least 90% of which iscapable of passing through a U. S. standard 400 mesh screen dispersed in60 to 70 fl. ozs. solution containing 40 to 60 per cent low acid resin,having an acid number not exceeding 6 in said solution, said solutionfurther containing up to fl. ozs. drying oil, 16 to 24 fl. ozs. solventand about 1 fl. oz. drier.

2. A liquid coating composition comprising a dispersion of 16 to lbs.zinc dust, the particle size of which is not larger than 6 microns andhaving an average particle size of 3 microns at least 90% of which iscapable of passing through a U. S. standard 400 mesh screen dispersed in60 to '70 fl. oz. solution containing 40 to 60 per cent low acid resin,having an acid number not exceeding 6 in said solution, said solutionfurther containing up to 10 fl. ozs. drying oil, 16 to 24 fl. ozs.solvent, about fl. oz. cobalt drier and /2 fl. oz. lead drier.

3. A liquid coating composition comprising a dispersion of 16 to 20 lbs.zinc dust, the particle size of which is not larger than 6 microns.

and having an average particle size of 3 microns at least 90% of whichis capable of passing through a U. S. standard 400 mesh screen dispersedin 60 to '70 fl. ozs. solution containing 40 to 60 per cent low acidresin, having an acid number not exceeding 6 in said solution, saidsolution further containing up to 10 11. ozs. drying oil, 16 to 24 ii.ozs. solvent and about 1 fl. oz. drier and .05 to .2 fl. oz. cresoteoil.

4. A liquid coating composition comprising a dispersion of 250 lbs. zincdust, the particle size of which is not larger than 6 microns and havingan average particle size of 3 microns at least 90% of which is capableof passing through a U. S. standard 400 mesh screen dispersed in 85 lbs.phthalic acid-glycerol resin solution containing 40 to 60% resin, saidsolution further containing about 10 lbs. raw linseed oil, about 32 lbs.mineral spirits, about 1 1b. lead linoleate, about 4 lb. cobaltlinoleate and about 2 ozs. creosote oil.

5. A liquid coating composition comprising a dispersion of 20 lbs. zincdust, the particle size of which is not larger than 6 microns and havingan average particle size of 3 microns at least of which is capable ofpassing through a U. S. standard 400 mesh screen dispersed in about 64fl. ozs. phenol formaldehyde resin solution containing 40 to 60% resin,about 8 fl. ozs. oiticica oil, about 16 fl. ozs. VM&P naphtha, about fl.oz. cobalt linoleate, about /2 fi. oz. lead naphthenate, and about fl.oz. creosote oil.

6. A liquid coating composition comprising a dispersion of 19 lbs. zincdust, the particle size of which is not larger than 6 microns and havingan average particle size of 3 microns at least 90% of which is capableof passing through a U. S. standard 400 mesh screen dispersed in about64 fl. ozs. phenol formaldehyde resin solution containing 40 to 60%resin, about 6 fl. ozs. perilla oil, about 18 fl. ozs. Stoddard solvent,about fl. oz. cobalt naphthenate, about /2 fl. oz. lead linoleate andabout fl. oz. creosote oil.

7. A liquid coating composition comprising a dispersion of 20 lbs. zincdust, the particle size of which is not larger than 6 microns and havingan average particle size of 3 microns at least 90% of which is capableof passing through a U. S. standard 400 mesh screen dispersed in about6'7 fl. ozs. alkyd resin solution containing 40 to 60% resin, about 1fl. oz. blown linseed oil, about 10 fl. ozs. toluol, about 10 fl. ozs.mineral spirits, about A fl. oz. cobalt naphthanate, about A 11. oz.lead naphthanate, and about /2 fl. oz. creosote oil.

8. A liquid coating composition comprising a dispersion of 20 lbs. ofzinc dust, the particle size of which is not larger than 3 microns, atleast 90% of which is capable of passing through a U. S. standard 400mesh screen dispersed in about 60 to 70 fl. ozs. solution containing 40to 60% phenol formaldehyde resin, having an acid number not exceeding 6in said solution, said solution further containing up to 10 fl. ozs.linseed oil, 16 to 24 fl. ozs. solvent and about 1 fl. oz. drier.

9. A liquid coating composition comprising a dispersion of 20 lbs. ofzinc dust, the particle size of which is not larger than 3 microns, atleast 90% of which is capable of passing through a U. S. standard 400mesh screen dispersed in about 60 to 70 fl. ozs. solution containing 40to 60% alkyd resin, having an acid number not exceeding 6 in saidsolution, said solution further containing up to 10 fl. ozs. drying oil,16 to 24 fl. ozs. solvent and about 1 fl. oz. drier.

JOHN R. FISHER, JR.

I REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,942,757 Iliff et al. Jan. 9,1934 2,346,624 Straus Apr. 11, 1944 2,436,420 Clayton Feb. 24, 19482,468,920 Brown et al. May 3, 1949 2,493,020 Osdal et al. Jan. 3, 19502,509,875 McDonald May 30, 1950 FOREIGN PATENTS Number Country Date115,134 Australia May 12, 1942

1. A LIQUID COATING COMPOSITION COMPRISING A DISPERSION OF 16 TO 20 LBS.ZINC DUST, THE PARTICLE SIZE OF WHICH IS NOT GREATER THAN 6 MICRONS ATHAVING AN AVERAGE PARTICLE SIZE OF 3 MICRONS AND LEAST 90% OF WHICH ISCAPABLE OF PASSING THROUGH A U. S. STANDARD 400 MESH SCREEN DISPESED IN60 TO 70 FL. OZS. SOLUTION CONTAINING 40 TO 60 PER CENT LOW ACID RESIN,HAVING AN ACID NUMBER NOT EXCEEDING 6 IN SAID SOLUTION, SAID SOLUTIONFURTHER CONTAINING UP TO 10 FL. OZS. DRYING OIL, 16 TO 24 FL. OZS.SOLVENT AND ABOUT 1 FL.OZ. DRIER.